在Spock中使用GroovyMock或类似的模拟静态方法

Question

public class ClassUnderTest{

public void methodUnderTest(Parameter param){
  //everything else commented out
Thing someThing = ClassWithStatic.staticMethodThatReturnsAnInstance().instanceMethod(param);
   }

}

def exerciseTheStaticMock(){
    given:
    def globalMock = GroovyMock(ClassWithStatic,global: true)
    def instanceMock = Mock(ClassWithStatic)

    when:
    println(ClassWithStatic.staticMethodThatReturnsAnInstance().instanceMethod(testParam))

    then:
    interaction{
        1 * ClassWithStatic.staticMethodThatReturnsAnInstance() >> instanceMock
        1 * instanceMock.instanceMethod(_) >> returnThing
    }
}

但是如果我从ClassUnderTest运行methodUnderTest：

def failingAttemptToGetPastStatic(){
    given:
    def globalMock = GroovyMock(ClassWithStatic,global: true)
    def instanceMock = Mock(ClassWithStatic)
    ClassUnderTest myClassUnderTest = new ClassUnderTest()

    when:
    myClassUnderTest.methodUnderTest(testParam)

    then:
    interaction{
        1 * ClassWithStatic.staticMethodThatReturnsAnInstance() >> instanceMock
        1 * instanceMock.instanceMethod(_) >> returnThing
    }
}

它抛出了一个ClassWithStatic的真实实例，该实例在其实例Method中失败。